1. Field of the Invention
The present invention relates to a method for providing a digital content, and more particularly to a method for providing a digital content wherein a playback information package generated according to a playback sequence of a main digital content and an auxiliary digital content is used to facilitate a configuration of a playback apparatus supporting a BD-J specification.
2. Description of the Related Art
A Blu-ray specification is designed by Blu-ray Disc Association (“BDA”), whose members include Sony, Hitachi and Sharp. The Blu-ray specification includes a specification of a Blu-ray disk which is an optical disc that may be read and recorded using a blue laser.
While a diameter and a thickness of the Blu-ray disk, which are 12 cm and 1.2 mm, respectively, are same as those of conventional CD (Compact Disc) and DVD (Digital Versatile Disc), a storage capacity thereof is larger than those of the conventional CD and DVD.
Because the blue laser having a wavelength of 405 nm is used for reading the Blu-ray disk instead of a red laser having a wavelength of 650 nm used for reading the DVD, more data can be stored in the Blu-ray disk than the DVD.
Specifically, a single layer Blu-ray disk is capable of storing up to 25 GB of a data and a dual layer Blu-ray disk is capable of storing up to 50 GB of the data. This means that the Blu-ray disk can store five times more data than the DVD.
Moreover, a quad layer Blu-ray disk and an octal layer Blu-ray disk can store up to 100 GB and 200 GB, respectively.
The Blu-ray disk supports a video compression codec of MPEG-2 which is widely used in the DVD. Moreover, BDA standard specification requires the Blu-ray disk to use H.264/AVC or VC-1 as the video compression codec which provides improved compression ratio compared to MPEG-2.
In addition, the Blu-ray disk supports audio formats such as Dolby Digital Plus, Dolby TrueHD and DTS-HD Master Audio as well as PCM (Pulse-code modulation), Dolby Digital and DTS.
A Blu-ray player supporting a BD-J specification supports an interactive service based on JAVA. Moreover, the Blu-ray player supporting the BD-J specification supports a network connectivity, a PIP (Picture-In-Picture) and a connection to a local storage.
A Blu-ray player supporting a BD-Live specification is capable of playing a digital content received through a network communication in addition to capabilities of the Blu-ray player supporting a BD-J specification.
A Virtual File System (“VFS”) enables a playback of a data which is not stored on the Blu-ray disk. Specifically, the VFS configures a virtual package on the Blu-ray player to enable the Blu-ray player to play the data stored in other than the Blu-ray disk. For instance, the digital content received through a USB or the network communication may be played as if the digital content is stored in the Blu-ray disk.
Hereinafter, “a playback apparatus supporting the BD-J specification” includes the Blu-ray player supporting the BD-J specification or an apparatus using a middleware supporting the BD-J specification such as a TV, a set-top box, a PMP (Portable Multimedia Player), a video game console, a PC (Personal Computer) and a PVR (Personal Video Recorder).
The apparatus using the middleware supporting the BD-J specification is not required to have a Blu-ray disk reading capability.
FIG. 1 is a diagram illustrating a configuration for receiving a digital content via a network in a conventional playback apparatus supporting a BD-J specification.
A digital content providing server generates a BUMF (Binding Unit Manifest File) information, an SF (Signature File) information, a playlist information, movie clips and a clip information associated with each of the movie clips according to the BD-J specification.
The BUMF information defines a configuration of a virtual package in XML (Extensible Markup Language) format. For instance, the BUMF information includes a file name information and a binding information on the movie clips included in the digital content received from the digital content providing server.
The SF information is used for verifying a validity of the BUMF information. The SF information uses SHA (Secure Hash algorithm)-1.
The playlist information includes an information on the digital content to be played. For instance, the playlist information includes a playback sequence information, a PlayItem information and a PlayListMark information on the movie clips included in the digital content.
The clip information includes an information required for playing the movie clips. For instance, the clip information includes a stream format information of the corresponding clip, a number of packets included in the corresponding clip, an encoding specification of the corresponding clip and a time stamp information.
The playback apparatus stores the BUMF information, the SF information, the playlist information and the clip information received from the digital content providing server in a BUDA (Binding Unit Data Area). The playback apparatus carries out a package update from a disk package to the virtual package based on the BUMF information, the SF information, the playlist information and the clip information stored in the BUDA. That is, the playback apparatus is configured to play the digital content received from the digital content providing server instead of playing a data stored in the Blu-ray disk.
When the playback apparatus is fully configured, the playback apparatus receives and plays the digital content from the digital content providing server.
In order to play the digital content received from the digital content providing server, the playback apparatus must identify a size of the digital content, the number of clips included in the digital content, a encoding algorithm of the clip and a validity verification information by receiving the BUMF information, the SF information, the playlist information and the clip information from the digital content providing server.
In addition, the playback apparatus may provide an auxiliary digital content from an auxiliary digital content providing server.
That is, when a user selects a main digital content, the digital content providing server transmits the selected main digital content along with the auxiliary digital content to the playback apparatus.
For instance, when the user selects one of movies via a VOD (video on demand), the digital content providing server transmits the auxiliary digital content such as a pre-roll advertisement provided prior to the playback of the selected movie and post-roll advertisement provided after the playback of the selected movie to the user as well as the main digital content, i.e. the selected movie. Preferably, in order to provide a user-specific auxiliary digital content, a separate server for providing the auxiliary digital content, i.e. the auxiliary digital content providing server is employed to enable a transmission of the auxiliary digital content to the playback apparatus.
Therefore, the playback apparatus must carry out a package update for the auxiliary digital content as well as the main digital content in order to play both the main digital content and the auxiliary digital content received from the digital content providing server.
That is, the playback apparatus stores the BUMF information, the SF information, the playlist information and the clip information on each of the main digital content and the auxiliary digital content received from the digital content providing server in a BUDA (Binding Unit Data Area). The playback apparatus carries out a package update from a disk package to the virtual package based on the BUMF informations, the SF informations, the playlist informations and the clip informations stored in the BUDA. When the playback apparatus is fully configured, the playback apparatus sequentially receives and plays the main digital content and the auxiliary digital content including the movie clips.
FIG. 2 is a diagram illustrating an example for configuring a virtual package according to a main digital content and an auxiliary digital content in a conventional playback apparatus supporting a BD-J specification.
The digital content providing server stores a the main information on the main digital content. For instance, when the digital content providing server stores a plurality of movie data, the digital content providing server also stores the main information such as the BUMF information, the SF information, the playlist information and the clip information of each movie data in the XML format. Mov—1.xml through mov_m.xml shown in FIG. 2 represent the main information on the main digital content.
In addition, the digital content providing server or the auxiliary digital content providing server stores the auxiliary information on the auxiliary digital content. For instance, when the auxiliary digital content providing server stores a plurality of advertisement data, the auxiliary digital content providing server also stores the auxiliary information such as the BUMF information, the SF information, the playlist information and the clip information of each advertisement data in the XML format. Ad—1.xml through ad_n.xml shown in FIG. 2 represent the auxiliary information on the auxiliary digital content.
For instance, when the user selects one of the movies corresponding to mov—2.xml, the digital content providing server provides the advertisement data corresponding to ad—1.xml provided prior to the playback of mov—2.xml, and the advertisement data corresponding to ad—2.xml provided after the playback of mov—2.xml.
Accordingly, the playback apparatus configures the virtual package based on ad—1.xml which is the pre-roll advertisement, and the playback apparatus then receives, from the digital content providing server or the auxiliary digital content providing server, and plays the pre-roll advertisement.
Thereafter, the playback apparatus configures the virtual package based on mov—2.xml which is the selected movie, and the playback apparatus then receives, from the digital content providing server, and plays the selected movie.
Thereafter, the playback apparatus configures the virtual package based on ad—2.xml which is the post-roll advertisement, and the playback apparatus then receives, from the digital content providing server or the auxiliary digital content providing server, and plays the post-roll advertisement.
Therefore, a conventional playback apparatus shown in FIG. 2 configures the virtual package three times in order to play the main digital content and the auxiliary digital content received from the digital content providing server and the auxiliary digital content providing server.
That is, a long time is required to provide the main digital content selected by the user since the conventional playback apparatus is required to configure the virtual package for each of the main digital content and the auxiliary digital content.